import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;

public class Demo4 {
    public static void main(String[] args) throws IOException {
        InputStream  stream=new FileInputStream("./text.txt");
        //此处隐含了一个操作 “打开文件”
        stream.close();
    }
}
